Larvae and their Work 



ingenious shelters, they do not exhibit such wonderful 

 uniformity of architecture as the beetles. Another point 

 of difference is that the beetle larvae remain in their leafy 

 shelters, come what may, but the caterpillars of the leaf- 

 rolling moths, or, more correctly, the leaf-rolling cater- 

 pillars, when alarmed, leave their hiding-places and hang 

 from the leaves by silken threads which they spin them- 

 selves, only returning to their shelters when the danger be 

 over. Whatever surprise we may have felt that a creature 

 so small as the birch weevil could roll a birch leaf must 

 be intensified when we consider how it is possible for the 

 ofttimes exceedingly diminutive leaf-rolling caterpillars 

 to mould a living leaf to suit their purpose. These little 

 individuals perform some astounding engineering feats. 

 Let us see how they work. 



Diligent search on the part of the caterpillar has its 

 reward in the discovery of a leaf which is, maybe, ever so 

 slightly curved. Such a leaf makes a good starting-point 

 for the little engineer, whose first care is to run a number 

 of silken threads from the curved margin of the leaf to 

 a point as far as it can reach on the leaf blade. This 

 preliminary structure may be looked upon as a kind 'of 

 scaffolding from which the more useful part of the work 

 may be undertaken, for these first threads do not cause 

 the leaf to roll any more. Having spun a sufficiency of 

 silk for its purpose, the caterpillar climbs upon them and, 

 by pressing thereon, sets up a tension which causes the 

 leaf margin to be drawn a little nearer to the blade, ever 

 so little nearer certainly, but sufficient for the engineer's 

 purpose. 



Now the larva repeats its spinning operations, fixing its 

 new threads as far over on the convex side of the leaf curl 

 as possible and as far towards the centre of the leaf as 

 it can reach. From side to side the industrious little 

 creature's head waves as it spins, till at length it finishes 

 its system of stay ropes and the leaf has been pulled over 

 a shade more. The operation is repeated again and 



